TWI653155B - Microcontact printing method with high relief stamps in a roll-to-roll process and system using the same - Google Patents

Abstract

The present invention provides a method comprising: unwinding a web from a support and providing an elastomeric stamp, wherein the stamp comprises a bottom surface and a pattern element arrangement extending away from the bottom surface, and wherein each pattern element has a lateral dimension less than An embossed surface of about 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the lateral dimension is at least 1.5. The embossed surfaces of the patterned elements are inked with an ink composition comprising functionalized molecules, wherein the functionalized molecules comprise functional groups selected to bind to the substrate material. Contacting the embossed surface of the pattern elements with the major surface of the web for a sufficient amount to bond the functional group to the web to form a self-assembled monolayer of the functionalized material on the major surface of the web ( The printing time of the SAM) corresponds to the arrangement of the pattern elements on the embossed surface.

Description

Microcontact printing method with high relief stamp in roll-to-roll process and system using same

This invention relates to a printing method, and more particularly to a roll-to-roll microcontact printing method using a microcontact stamp having high aspect ratio printing features, and a system using the same.

Microcontact printing is a printing technique that can be used, for example, to create a pattern of functionalized molecules on the surface of a substrate. The functionalized molecules include functional groups that are attached to the surface of the substrate or to the surface of the coated substrate via chemical bonds to form a patterned self-assembled monolayer (SAM). The SAM is a single layer of molecules that are chemically bonded to the surface and that are preferably oriented relative to the surface and even relative to each other.

A basic method for microcontact printing of SAM involves applying an ink containing the functionalized molecules to an embossed patterned elastomeric seal (eg, a poly(dimethyl methoxide) (PDMS) stamp) and subsequently The ink stamp contacts the substrate surface (typically a metal or metal oxide surface) to form a SAM in the contact area between the stamp and the substrate. Alternatively, the elastomeric stamp can be flat (without embossed pattern) and the substrate surface can be embossed. Micropatterned organic and inorganic materials printed using microcontact printing may provide unique electrical, optical, and/or biological properties to substrates such as metallized polymeric films.

In a manufacturing process, the functionalized molecules should be reproducibly transferred from the stamp to the surface of the substrate in the form of the desired high resolution patterned SAM with a minimum number of defects. Pattern defects such as line blurring and voids should be minimized to ensure accurate SAM pattern resolution and reproducibility when increasing the microcontact printing speed on the moving material web in the roll-to-roll manufacturing process.

In general, the present invention is directed to a roll-to-roll microcontact printing method that utilizes a microcontact stamp having high aspect ratio printing features. In such a roll-to-roll manufacturing process, the high aspect ratio seal improves the fidelity of the printed SAM pattern on the substrate by reducing process-dependent line broadening. High aspect ratio stamps allow printing at higher line speeds without causing SAM defects associated with air inclusions and alleviating particle related defects in printed SAM.

In one embodiment, the present invention is directed to a method comprising unwinding a web from a support and providing an elastomeric stamp, wherein the stamp comprises a bottom surface and a pattern element arrangement extending away from the bottom surface, wherein each pattern element An embossed surface having a transverse dimension of less than about 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the lateral dimension is at least 1.5. The embossed surfaces of the patterned elements are inked with an ink composition comprising functionalized molecules, wherein the functionalized molecules comprise functional groups selected to bind to the substrate material. Contacting the embossed surface of the pattern elements with the major surface of the web for a sufficient amount to bond the functional group to the web to form a self-assembled monolayer of the functionalized material on the major surface of the web ( The printing time of the SAM) corresponds to the arrangement of the pattern elements on the embossed surface.

In another embodiment, the present invention is directed to a method comprising: stretching a web between a first roll and a second roll with a tension of at least about 0.1 pounds per linear nip, wherein the web is greater than about 10 Moving at a speed of 呎/min; mounting an elastomeric polymer stamp on a printing roll, wherein the stamp comprises a bottom surface and a pattern element arrangement having a trapezoidal cross-sectional shape and extending above the bottom surface, wherein the pattern elements each comprise a substantially flat transverse dimension of from about 0.25 microns to about 5 microns and an elevation relative to the bottom surface, and wherein the aspect ratio of the height to the transverse dimension is from about 1.5 to about 5.0; including organic sulfur compounds The ink composition inks the embossed surface; contacting the embossed surface with a major surface of the web between the first roll and the second roll for a printing time of from about 0.1 second to about 30 seconds, So that a functional group on the organosulfur compound is bonded to the major surface of the web to provide a self-assembled monolayer (SAM) of the organosulfur compound on the major surface, A self-assembled monolayer corresponds to an array of pattern elements on the embossed surface; and the embossed surface is removed from the major surface of the web.

In another embodiment, the present invention is directed to a method comprising: unwinding a web from a self-supporting roll, wherein the web moves at a speed greater than about 10 Torr/min; and poly(dimethyl methoxy oxane) a stamp mounted on the printing roll, wherein the stamp comprises a substantially flat bottom surface and a continuous regular array of pattern elements having a trapezoidal cross-sectional shape and extending above the bottom surface, wherein the pattern elements each have a substantially flat shape An embossed surface having a transverse dimension of from about 0.25 microns to about 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the transverse dimension is from about 1.5 to about 5.0; comprising an organic sulfur compound and an organic solvent The ink composition is inked onto the embossed surface; the embossed surface is contacted with the major surface of the web for a printing time of from about 0.1 second to about 30 seconds such that the thiol functional group on the organosulfur compound is incorporated The major surface of the web provides a self-assembled monolayer (SAM) of the organosulfur compound on the major surface, the self-assembled monolayer corresponding to an array of patterned elements on the embossed surface. The SAM includes a reduced one of at least one of the following, as compared to a SAM produced by a poly(dimethyloxane) seal comprising a pattern element having a trapezoidal cross-sectional shape and an aspect ratio of less than about 1.5 Incidence: (1) repeated defects; and (2) air inclusion defects. The embossed surface is then removed from the major surface of the web.

In another embodiment, the invention is directed to a system comprising a first roll and a second roll, and a web of moving material stretched between the first roll and the second roll. An elastomeric stamp is mounted on the roll and in contact with the web between the first roll and the second roll, wherein the stamp comprises a bottom surface and a pattern having a trapezoidal cross-sectional shape and extending above the bottom surface An arrangement of elements, wherein each of the pattern elements comprises a substantially flat embossed surface having a lateral dimension of from about 0.25 microns to about 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the lateral dimension is about 1.5 to about 5.0. The system further includes apparatus for inking the embossed surface with an organosulfur compound having a thiol functional group selected to bind to a major surface of the web to form on the major surface Self-assembled monolayer (SAM), the self-assembled monolayer corresponding to an array of patterned elements on the embossed surface.

The details of one or more embodiments of the invention are set forth in the description Other features, objects, and advantages of the invention will be apparent from the description and drawings.

10‧‧‧Microcontact printing seal/seal

11‧‧‧Enhanced backing/seal support

12‧‧‧Bottom surface/flat surface

14‧‧‧Pattern Components / Elastomer Pattern Components / Small Pattern Components / Micro Pattern Pattern Components / Imprint Components / Stamp Components

16‧‧‧imprinted surface/printed surface

18‧‧‧ channel

20‧‧‧Ink/ink solution

21‧‧‧Stained ink pattern

22‧‧‧Surface Materials/Materials/Substrate Materials/Inorganic Coatings/Metal Surfaces/Gold Coating

24‧‧‧Support layer/physical support layer/矽wafer substrate/polymer film/glass/矽 wafer

25‧‧‧The first part of the surface of the material

26‧‧‧Material Surface/Surface/Substrate Surface

27‧‧‧Continuous part of the first part of the surface of the material

30‧‧‧Self-assembled single layer / SAM

35‧‧‧Substrate

100‧‧‧Microcontact printing process line/process line

102‧‧‧Web/Substrate

104‧‧‧First support

106‧‧‧ Elastomeric seal/seal

107‧‧‧patterned surface/inking surface

108‧‧‧Printing roller

110‧‧‧Second nip rollers

111‧‧‧ Elastomeric layer

120‧‧‧Surface surface/substrate surface/surface/second embossed surface

200‧‧‧Microcontact printing process line/process line

202‧‧‧Web

204‧‧‧First Stretch Roller/Roller

206‧‧‧ Elastomeric seal/seal

208‧‧‧Printing roller

210‧‧‧Second stretching roller/roller

211‧‧‧ Elastomeric layer

300‧‧‧Microcontact printing process line/process line

302‧‧‧Web

304‧‧‧Single nip roller

306‧‧‧ Elastomeric seal/seal

308‧‧‧Printing roller

311‧‧‧ Elastomeric layer

400‧‧‧Microcontact printing process line/process line

402‧‧‧Web

404‧‧‧ pinch roller

406‧‧‧ Elastomeric seal/seal

408‧‧‧Printing roller

410‧‧‧ stretching rolls

411‧‧‧ Elastomeric layer

506‧‧‧ Seal

508‧‧‧Printing roller/roller

509‧‧‧Fluid coupling

509A‧‧‧ hollow interior area

511‧‧‧ Elastomeric layer

The invention will be more fully understood from the following detailed description of the embodiments of the invention. Limiting the broader aspects of the invention.

1 is a schematic cross-sectional view of one embodiment of a high aspect ratio seal for microcontact printing.

2 is a schematic cross-sectional view of another embodiment of a high aspect ratio seal for microcontact printing.

3 is a schematic cross-sectional view of a process for forming a self-assembled monolayer (SAM) on a substrate using a high aspect ratio stamp in a microcontact printing process.

4A and 4B are schematic cross-sectional views of a stamp for microcontact printing utilized in a process for moving a substrate relative to a stamp.

Figure 5 is a schematic illustration of a portion of an apparatus having dual nip rolls and an extended process zone for use in microcontact printing in a roll-to-roll process.

Figure 6 is a schematic illustration of a portion of a stretch web apparatus having twin rolls used in microcontact printing in a roll-to-roll process.

Figure 7 is a schematic illustration of a portion of a device having a single nip roll used in microcontact printing in a roll-to-roll process.

Figure 8 is a schematic illustration of a portion of an apparatus having a single nip roll and an extended process zone for use in microcontact printing in a roll-to-roll process.

Figure 9 is a schematic illustration of a printing roller and a fluid coupling of a stamp in a microcontact printing apparatus Cross-sectional view.

Figure 10 is a schematic illustration of the molded surface of the microcontact printing stamp utilized in Example 2.

Figure 11 is a graph of the force of each stamp width of the molded microcontact printing stamp of Example 2 versus the substrate displacement.

While the above-described embodiments are not necessarily to scale, the various embodiments of the invention are described, The same symbols in the figures indicate the same elements.

All numbers expressing the size, quantity, and physical properties of the features used in the specification and claims are to be understood as being modified by the term "about" in all instances. Accordingly, the numerical parameters set forth in the foregoing specification and the appended claims are intended to be an approximation that can be varied by the skilled person in the <RTIgt; In no way is meant to limit the application of the theory of equalization to the scope of the claimed embodiments, the numerical parameters being interpreted at least in accordance with the number of significant digits reported and by applying the general rounding technique. In addition, use of a range of values with endpoints includes all numbers within the range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any narrower range or single within the range value.

Glossary:

Certain terms used in the description and claims are mostly well known and may require some explanation. It should be understood that as used herein, the terms "about", "approximate", or "approximately" mean a value or a geometry having a generally recognized number of sides when referring to a numerical value or geometric shape. +/- 5% of the value of the inner edge of the shape, including any narrower range and exact value or angular value within the value or angle value +/- 5%. For example, "about" a temperature of 100 ° C means a temperature of from 95 ° C to 105 ° C, but also includes any narrower temperature range or even a single temperature within the range, including, for example, a temperature of exactly 100 ° C. same, The "roughly square" geometry includes all four-sided geometries with an inner corner of 85-95 degrees, since the 90-degree inner corner corresponds to a perfect square geometry.

The term "substantially" when referring to a property or property means that the property or property exhibited is within 98% of the property or property, but also explicitly includes any narrower range within 2% of the property or property and The exact value of the property or characteristic. For example, a "substantially" transparent substrate refers to a substrate that transmits 98% to 100% of incident light.

Unless the context clearly dictates otherwise, the terms "a/an" and "the" include plural referents. Thus, for example, reference to a material containing "a compound" includes a mixture of two or more compounds.

The term "or" is generally used in its meaning including "and/or" unless the context clearly dictates otherwise.

Various illustrative embodiments of the invention are now described with reference to the specific drawings. Various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, it is to be understood that the embodiments of the invention are not limited to the exemplified embodiments described below, but are limited by the scope of the claims and any equivalents thereof.

1 shows a schematic illustration of a microcontact printed stamp 10 that includes a substantially flat bottom surface 12. The array of pattern elements 14 extends away from the bottom surface 12. In some embodiments, the stamp 10 is a monolithic block of elastomeric material, while in other embodiments an elastomeric pattern element 14 supported by the reinforcing backing layer 11 as the case may be included. The array of pattern elements 14 on the bottom surface 12 of the stamp 10 can vary widely depending on the intended microcontact printing application, and can include, for example, regular or irregular element patterns such as lines, dots, and polygons.

The pattern elements 14 in the array on the bottom surface 12 can be described in terms of their shape, orientation and size. The pattern element 14 has a bottom width x at the bottom surface 12 and includes an embossed surface 16. The embossed surface 16 is at a height h above the bottom surface 12 and has a lateral dimension w which may be the same or different than the bottom width x . The aspect ratio h / w of the pattern element 14 is at least about 1.5. In various embodiments, the aspect ratio of the height h of the pattern element 14 to the width w of the stamping surface 16 of the pattern element 14 is from about 1.5 to about 5.0, from about 1.5 to about 3.0, or from about 1.5 to about 2.0.

The methods and apparatus described herein are particularly advantageous for small pattern elements 14 having an embossed surface 16 having a minimum lateral dimension w of less than about 10 μm or less than about 5 μm or less than about 1 μm. In the embodiment shown in Figure 1, the embossed surface 16 is substantially flat and substantially parallel to the bottom surface 12, but such parallel alignment is not required. The methods and apparatus reported herein are also particularly advantageous for utilizing a height h of about 50 μm or less, or about 10 μm or less, or about 5 μm or less, or about 1 μm or less, or about 0.25 μm or less. The pattern element 14 is microcontact printed.

The pattern element 14 can occupy the entire bottom surface 12 or occupy only a portion (some areas of the bottom surface 12 can be free of pattern elements). For example, in various embodiments, the spacing 1 between adjacent pattern elements can be greater than about 50 [mu]m or greater than about 100 [mu]m or greater than about 200 [mu]m or greater than about 300 [mu]m or greater than about 400 [mu]m or even greater than about 500 [mu]m. The commercially available array of pattern elements 14 for microcontact printing covers an area of the bottom surface 12 of the stamp 10, for example, greater than 100 cm ² , greater than 200 cm ² or even greater than 1000 cm ² .

In some embodiments, pattern element 14 may form a "micropattern," which in the present application refers to an arrangement of dots, lines, fill shapes, or combinations thereof, having a dimension (eg, line width) of no more than 1 mm. In some embodiments, the size (eg, line width) of the arrangement of dots, lines, fill shapes, or a combination thereof is at least 0.5 [mu]m and typically no greater than 20 [mu]m. The size of the micropattern pattern element 14 may vary depending on the micropattern selection, and in some embodiments, the size of the micropattern pattern element (eg, line width) is less than 10, 9, 8, 7, 6, or 5 [mu]m (eg, 0.5-5 [mu]m or 0.75-4 μm).

In some embodiments, the pattern elements are traces that can be straight or curved. In some embodiments, the pattern elements are traces that form a two-dimensional web (ie, a screen). Screen Contains traces that define open cells. The screen may be, for example, a checkered, hexagonal screen or pseudo-random screen. Pseudo-random means that the trace arrangement lacks translational symmetry, but may be derived from a deterministic manufacturing process (eg, photolithography or printing), including, for example, a computational design process that includes generating a pattern geometry using a random algorithm. In some embodiments, the screen has an open area fraction of between 90% and 99.75% (ie, the density of the pattern elements is between 0.25% and 10%). In some embodiments, the screen has an open area fraction of between 95% and 99.5% (ie, the density of the pattern elements is between 0.5% and 5%). The pattern elements can have a combination of the above, for example they can be curved traces, form a pseudo-random screen, have a density between 0.5% and 5%, and have a width between 0.5 μm and 5 μm.

In one embodiment of the stamp 10 shown schematically in Figure 2, the pattern element 14 has a trapezoidal cross-sectional shape having a bottom width r , a height h above the bottom surface 12 and a vertical angle θ. The pattern element 14 has a spacing l and an embossed surface 16 having a width w . In the embodiment shown in FIG. 2, the embossed surface 16 extends along substantially parallel lines on the bottom surface 12 of the stamp 10 to form a checkered arrangement. The area between the lines of the pattern elements 14 thus forms a channel 18. Many different configurations are possible. For example, in some embodiments, the embossed surface is a hexagon defined by pattern elements in the form of lines that define a hexagonal mesh similar to a two-dimensional mesh network (see, eg, Figure 10). . The aspect ratio of the pattern elements of the embodiment illustrated in Figure 2 is given by h/w .

Referring to FIG. 3, ink 20 comprising functionalized molecules resides on stamping surface 16 of stamp 10. The functionalized molecules in ink 20 include functional groups selected to bind selected surface material 22 on support layer 24 of substrate 35. The stamp 10 is positioned and brought into contact with the surface 26 of the material 22, and the embossed surface 16 is held against the first portion 25 of the surface 26 on the material 22. The functionalized molecules in the ink 20 are maintained against the surface 26 to allow the functional groups to bind thereto (the retention step is not shown in Figure 3). Subsequently, the embossed surface 16 is removed and the ink remaining on the surface 26 chemically bonds to the surface and forms a self-assembled monolayer (SAM) 30 on the portion 25 of the surface 26, the self-assembled monolayer corresponding to the embossed surface 16 shape and size. Surface 26 and first Portion 25 of portion 25 remains free of SAM 30.

The methods, apparatus, and printing stamps described herein are particularly advantageous for printing on flexible substrates in a roll-to-roll process. The flexible substrate is typically an elongated web of material having a length that is much greater than its width. In some embodiments, the flexible substrate can wrap around a circumference of a cylinder having a diameter of less than about 50 centimeters (cm) without twisting or breaking it. The selected substrate is preferably capable of wrapping around the circumference of the cylinder having a diameter of less than about 25 cm without distorting or breaking the substrate. In some embodiments, the selected substrate is preferably capable of wrapping around a circumference of a cylinder having a diameter of less than about 10 cm or even a diameter of about 5 cm without distorting or breaking the substrate. The forces used to wrap the flexible substrate of the present invention around a particular cylinder are generally low, such as by unassisted hands, i.e., without the aid of levers, machinery, hydraulics, and the like. Preferably, the flexible substrate itself can be wound.

In some embodiments, the flexible substrate material is a polymeric "film", i.e., a polymeric material in the form of a flat sheet or web that is flexible and strong enough to be processed in a roll-to-roll manner. In some embodiments, the polymeric film web comprises a relatively thin metal coating on a surface that will be coated with ink from the stamp. The metal coating can vary widely depending on the intended application, but should be thin enough to maintain the web in its flexibility, as defined above.

The thickness of these materials allows for roll-to-roll processing, which in some embodiments can be continuous, providing economies of scale and manufacturing economy for some flat and/or rigid substrates. In the present application, roll-to-roll refers to a process in which a material is wound onto a support or unwound from a support and may be further processed to some extent, as appropriate. Examples of other processes include coating, cutting, masking, and exposure to radiation or the like.

Polymer films suitable for roll-to-roll processing can be manufactured in a variety of thicknesses, typically in the range of from about 5 [mu]m to about 1000 [mu]m. In many embodiments, the polymeric film thickness is in the range of from about 25 [mu]m to about 500 [mu]m, or in the range of from about 50 [mu]m to about 250 [mu]m, or in the range of from about 75 [mu]m to about 200 [mu]m.

If the substrate 35 is relatively moved relative to the stamp 10, such as if the substrate 35 is a roll-to-roll manufacturing The smudge of the ink 20 may appear on the surface 26 as the moving material web in the process. For example, such smear can produce a SAM 30 (Fig. 3) having a line width that is longer and/or wider than the size of the printed surface 16, thereby resulting in a pattern represented by the array of pattern elements 14 and the resulting print on surface 26. Poor fidelity between SAMs 30. This relative movement between the stamp 10 and the substrate 35 begins when the tangential (frictional) stress between the surface 26 and the printed surface 16 of the stamp exceeds a predetermined value. Since the speed of the moving substrate 35 fluctuates, there is always a certain amount of mismatch between the surface 26 and the stamp 10. The detachment of the surface 26 from the embossed surface 16 can be affected by at least one of: (1) the elastomeric nature of the pattern element 14 and/or the stamp support 11 as the case may be, and (2) the pattern element 14 aspect ratio. Careful control of these parameters can reduce stress at the interface between the substrate surface 26 and the embossed surface 16.

As schematically shown in FIG. 4A, if the embossing element 14 is deformed when a mismatch occurs between the substrate surface 26 and the embossed surface 16, the pattern of the ink 20 can be accurately transferred from the embossed surface 16 to the surface 26 of the substrate. The line width in the resulting SAM 30 is not widened (in other words, the line width of the imprint surface 16 on the stamp 10 is substantially the same as the line width in the SAM 30). However, as shown in FIG. 4B, if the stamp member 14 does not deform when the substrate/seal speed mismatch occurs, slip occurs at the substrate/seal interface, and the resulting stained ink pattern 21 is opposed to the imprinted surface on the stamp 10. The width w of 16 widens the distance δ, thereby reducing the fidelity of the transfer of the ink 20 from the stamp 10 to the substrate surface 26.

Among the selected seal materials, the method claimed by the present invention is based, at least in part, on the discovery that when there is a speed difference and a relative displacement at the substrate/seal interface, the pattern elements having an aspect ratio greater than about 1.5 tend to deform more effectively (bending ). This deformation reduces the stress at the substrate/seal interface, thereby reducing the tendency of the embossed surface 16 to slide and widen on the substrate 26 or to stain the ink 20 and the resulting SAM 30. Since the hardness of the rod is proportional to the cube of its length, the aspect ratio effect of the pattern element 14 is significant. For example, for the same relative displacement, the frictional force of the pattern element 14 at the embossed surface 16 will be almost one tenth.

In the roll-to-roll process in which the substrate surface 26 moves rapidly relative to the stamp 10, as the printing speed increases, more air is trapped between the stamp 10 and the surface 26 of the substrate 35. When the thickness of the trapped air becomes greater than the approximate height h of the pattern element 14 (Fig. 1), no contact is established between the stamp surface 16 and the substrate surface 26 and a larger area of the surface 26 that is somewhat irregular will Missing printing. Thus increasing the aspect ratio and height h of the pattern element 14 allows for microcontact printing at higher speeds, and the stamp 10 can be operated without the presence of a thicker entrained air layer without producing print defects.

Moreover, if the powdered particles are trapped between the substrate surface 26 and the stamp 10, the stamping surface 16 may lose contact with the surface 26 and create an unprinted area on the substrate 26. The higher the aspect ratio of the pattern element 14, the greater the height h , thereby allowing larger powder particles to remain without creating unprinted areas on the substrate surface 26.

As noted above, the stamp 10 should be resilient such that the stamping surface 16 can conform very closely to the slight irregularities in the surface 26 of the material 22 and completely transfer the ink 20 thereto. This elasticity allows the stamp 10 to accurately transfer the functionalized molecules in the ink 20 to the uneven surface. However, the elasticity of the pattern element 14 should not cause the pattern element 14 to deform to a degree that obscures the ink 20 on the substrate surface 26 when the embossed surface 16 is slightly pressed against the surface 26.

The stamp 10 should also be formed such that the stamping surface 16 includes an absorbent material selected to absorb the ink 20 which will be transferred to the surface 26 to form the SAM 30 on the surface. The embossed surface 16 is preferably expanded to absorb the ink 20, which may include functionalized molecules that are only functionalized molecules or suspended in a carrier such as an organic solvent. This expansion and absorption characteristics well define the isolated SAM 30 on the substrate surface 26. For example, if the sizing features of the embossed surface 16 have a particular shape, the surface 16 should transfer the ink 20 to the surface 26 of the material 22 to form a SAM 30 that reflects the features of the embossed surface 16 without blurring or contamination. The ink is absorbed into the embossed surface 16, and when the embossed surface 16 contacts the surface 26 of the material, the ink 20 does not disperse, but the functional groups on the functionalized molecule are chemically bonded to the surface 26 and the pressure is removed from the surface 26. The printed surface 16 produces a SAM 30 having well-defined features.

Elastomers suitable for forming stamp 10 include polymers such as anthrone, polyurethane, ethylene propylene diene (EPDM) rubber, and commercially available flexographic printing plate materials (for example, available under the trade name Cyrel from EI) Du Pont de Nemours and Company, Wilmington, DE). The stamp may be fabricated from a composite material including, for example, an elastomeric material on the embossed surface 16 in combination with a woven or non-woven fiber reinforcement 11 (Fig. 1).

Polydimethyloxane (PDMS) is especially useful as a seal material because it is an elastomer and has a low surface energy (this property makes it easy to remove the stamp from most substrates). Commercially available formulations are available from Dow Corning, Midland, MI under the trade name Sylgard 184 PDMS. The PDMS stamp can be formed, for example, by dispensing or non-crosslinking the non-crosslinked PDMS polymer into a patterned mold, followed by curing. The master tool used to mold the elastomeric stamp can be formed using photolithography techniques known in the art. The elastomeric stamp can be molded by applying uncured PDMS to the master tool to the master tool and then curing.

Material 22 and ink 20 are selected such that the functionalized molecules therein include functional groups that can bind to surface 26 of material 22. The functional group can be at the physical end of the functionalized molecule, as well as any portion of the molecule that can be used to form a bond with the surface 26 in a manner that the molecular species can form the SAM 30, or any molecular moiety that is still exposed when the molecule is involved in SAM formation. In some embodiments, the functionalized molecule in ink 20 can be considered to have a first end and a second end separated by a spacer portion, the first end comprising a functional group selected to bond to surface 26, and the The two terminal groups optionally include a functional group selected to provide SAM 30 on the surface 26 of the material having the desired functionality to be exposed. The spacer portion of the molecule can be selected to provide a particular thickness of the resulting SAM 30 and to promote SAM formation. While the SAM of the present invention can vary in thickness, SAMs having a thickness of less than about 50 Å are generally preferred, more preferably less than about 30 Å thick, and more preferably less than about 15 Å thick. These dimensions are generally governed by the choice of molecular species 20 and, in particular, the spacing thereof.

Additionally, the SAM 30 formed on the surface 26 can be modified for various purposes after it is formed. For example, a functionalized molecule in ink 20 can be deposited in a SAM on surface 26 having an exposed functionality, including a protecting group that can be removed to achieve further modification of SAM 30. Alternatively, a reactive group can be provided on the exposed portion of the functionalized molecule in ink 20, which group can be activated or passivated by electron beam lithography, x-ray lithography, or any other radiation. Such protection and removal protection can aid in the chemical or physical modification of the existing surface in combination with SAM 30.

The substrate surface 26 made of material 22 is the surface on which the SAM 30 is formed. The term substrate 35 also optionally includes a physical support layer 24 below the surface material 22. In some embodiments, the substrate surface 26 is substantially flat. Suitable substrate material 22 may include a coating of an inorganic material (e.g., a metal or metal oxide material, including a polycrystalline material) on polymer film 24 or on glass or tantalum wafer 24. The inorganic material coating 22 can include, for example, elemental metals, metal alloys, intermetallic compounds, metal oxides, metal sulfides, metal carbides, metal nitrides, and combinations thereof. Exemplary metal surfaces 22 for supporting SAM include gold, silver, palladium, platinum, rhodium, copper, nickel, iron, indium, tin, antimony, aluminum, and mixtures, alloys, and compounds of such elements. Gold is the preferred metal surface 22.

The metal coating 22 on the polymeric film or glass or tantalum wafer substrate 24 can be of any thickness, such as from about 10 nanometers (nm) to about 1000 nm. The inorganic material coating can be deposited using any convenient method, such as sputtering, evaporation, chemical vapor deposition, or chemical solution deposition (including electroless plating).

Preferred combinations of functional groups of material 22 and functionalized molecules in ink 20 include, but are not limited to: (1) metals such as gold, silver, copper, cadmium, zinc, palladium, platinum, mercury, lead, iron, chromium, Manganese, tungsten and any alloy of the above) and sulfur-containing functional groups (such as thiols, sulfides, disulfides and the like); (2) doped or undoped ruthenium and decane and chlorine矽 ;; (3) metal oxides (such as cerium oxide, aluminum oxide, quartz, glass, and the like) and carboxylic acids; (4) platinum and palladium with nitriles and isonitriles; and (4) copper and hydroxyindoles acid. Ink 20 Other suitable functional groups on the functionalized molecule include acid chlorides, acid anhydrides, sulfonyl groups, phosphonium groups, hydroxyl groups, and amino acid groups. Other surface materials 22 include germanium, gallium, arsenic, and gallium arsenide. In addition, epoxy compounds, polyfluorene compounds, plastics, and other polymers can be used as the material 22. Other materials and functional groups suitable for use in the present invention are available in U.S. Patent Nos. 5,079,600 and 5,512,131.

In some embodiments, the functionalized molecules used to form the SAM in the process described in the present invention are delivered as an ink solution 20 comprising one or more organic sulfur compounds as described in US Patent Application Publication No. 2010/0258968 To the seal 10. Each organosulfur compound is preferably a thiol compound capable of forming SAM 30 on selected surfaces 26 of material 22. Mercaptans include the --SH functional group and may also be referred to as mercaptan. The thiol group is suitable for forming a chemical bond between the functionalized compound molecule in the ink 20 and the metal surface 22. Suitable mercaptans include, but are not limited to, alkyl mercaptans and aryl mercaptans. Other suitable organic sulfur compounds include dialkyl disulfides, dialkyl sulfides, alkyl xanthates, dithiophosphates, and dialkyl thiocarbamates.

The ink solution 20 preferably comprises an alkyl thiol such as a linear alkyl thiol: HS(CH ₂ ) _n X wherein n is the number of methylene units and X is the terminal group of the alkyl chain (eg X=-- CH ₃ , ---OH, --COOH, --NH ₂ or the like. Preferably, X = -CH ₃ . Other suitable functional groups include, for example, the functional groups described in (1) Ulman, "Formation and Structure of Self-Assembled Monolayers", Chemical Reviews, Vol. 96, pp. 1533-1554 (1996); and (2) Love et al., "Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology", Chemical Reviews, Vol. 105, pp. 1103-1169 (2005).

Suitable alkyl mercaptans may be linear alkyl mercaptans (i.e., straight chain alkyl mercaptans) or branched chains, and may be substituted or unsubstituted. Substituents which are optionally present do not interfere with the formation of the SAM. Examples of suitable branched alkyl mercaptans include methyl groups An alkylthiol (e.g., phytoalkylthiol) attached to every third or every fourth carbon atom of the backbone of the linear alkyl chain. Examples of suitable intermediate chain substituents in the alkylthiol include ether groups and aromatic rings. Suitable thiols may also include three-dimensional cyclic compounds such as 1-adamantanethiol.

Preferably, the linear alkyl thiol has 10 to 20 carbon atoms (more preferably 12 to 20 carbon atoms; most preferably 16 carbon atoms, 18 carbon atoms or 20 carbon atoms).

Suitable alkyl mercaptans include the commercially available alkyl mercaptans (Aldrich Chemical Company, Milwaukee, WI). Preferably, ink solution 20 consists essentially of a solvent and an organic sulfur compound, wherein the impurities comprise less than about 5% by weight of the ink solution; more preferably less than about 1%; even more preferably less than about 0.1%. Suitable ink 20 may contain a mixture of different organosulfur compounds dissolved in a conventional solvent, such as a mixture of an alkylthiol and a dialkyl disulfide.

An aryl thiol comprising a thiol group attached to an aromatic ring is also suitable for the ink 20. Examples of suitable aryl thiols include biphenyl thiol and terphenyl thiol. Biphenyl and terphenylthiol can be substituted with one or more functional groups at any of a variety of positions. Other examples of suitable aryl thiols include fused thiols which may or may not be substituted with a functional group.

Suitable thiols may include linear conjugated carbon-carbon bonds, such as double or para-bonds, and may be partially or fully fluorinated.

The ink solution 20 may include two or more chemically unique organic sulfur compounds. For example, the ink can include two linear alkyl thiol compounds, each having a different chain length. As another example, ink 20 can include two linear alkyl thiol compounds having different tail groups.

Although the seal has been inked for microcontact printing using pure organic sulfur compounds, in the case of linear alkyl mercaptan and PDMS stamps, organic sulfur compounds can be more uniformly delivered by solvent-based inks. Delivered to the stamp with less stamp expansion. In some embodiments, the ink includes more than one solvent, but most suitable formulations need to include only a single solvent. The ink formulated with only one solvent may contain a small amount of impurities or additives such as a stabilizer or a desiccant.

Suitable solvents are preferably compatible with PDMS (i.e., they do not overextend PDMS), and PDMS is the most commonly used stamp material for microcontact printing. In microcontact printing, the expansion of the PDMS stamp can cause pattern distortion and poor pattern fidelity. Depending on the ink method, excessive expansion can also present significant challenges in providing mechanical support for the seal.

The ketone can be a solvent suitable for use in an ink solution. In some embodiments, suitable solvents include, for example, acetone, methyl ethyl ketone, ethyl acetate, and the like, and combinations thereof. Acetone is a preferred solvent. The one or more organosulfur compounds (eg, thiol compounds) are present in the solvent at a total concentration of at least about 3 millimolar (mM). As used herein, "total concentration" refers to the total molar concentration of all dissolved organosulfur compounds. The one or more organosulfur compounds (e.g., thiol compounds) can be present in any total concentration, wherein the ink solution consists essentially of a single phase. The one or more organosulfur compounds (eg, thiol compounds) can be present in a total concentration of at least about 5 mM, at least about 10 mM, at least about 20 mM, at least 50 mM, and even at least about 100 mM.

The seal 10 can be "inked" using the ink solution 20 of the present invention using methods known in the art (e.g., as Libioulle et al., "Contact-Inking Stamps for Microcontact Printing of Alkanethiols on Gold", Langmuir, Vol. 15, As described in pages 300-304 (1999). In one method, an applicator (e.g., a cotton or foam applicator) that infuses the ink solution 20 can be used to rub the stamping surface 16 of the stamp 10, followed by drying of the solvent on the stamping surface 16. In another method, the embossed surface 16 can be pressed against an "ink pad" that is infused with an ink solution, which is optionally a PDMS plate. In another method, the stamp can be filled with an ink solution from its back side relative to the printing surface. In the latter method, the organosulfur compound diffuses through the stamp to the relief patterned surface (which includes the planar surface 12 and the patterned element 14 having the embossed surface 16) for printing. In another embodiment, the embossed patterned print surface of the stamp can be immersed in the ink solution, then removed and dried ("immersion in ink").

In another embodiment, the stamp 10 can be mounted on a printing roll and the embossed surface can be made 16 is offset from the moving web to form a SAM thereon. The printing roll is preferably cylindrical. It will be understood by those skilled in the art that cylindrical rollers may deviate from the ideal, such as eccentricity, eccentricity or wedge shape. Preferably, the cylindrical printing roll of the present invention has a radius of between 2 cm and 50 cm, more preferably between 5 cm and 25 cm, most preferably between 7.5 cm and 20 cm. For stamps having a small thickness and a total dimension of the mounting member relative to the radius of the printing roll (e.g., less than 1 cm in total), the radius of curvature of the stamp mounted on the printing roll is preferably between 2 cm and 50 cm, more preferably between 5 cm and Between 25cm, preferably between 7.5cm and 20cm.

In some embodiments, the rotation of the printing roll is synchronized with the movement of the web. Examples of selected embodiments of this type are described in greater detail below. This rotation and the simultaneous movement of such movement means that for the moving web, the embossed surface and the moving web are translated in translation when they are in contact, thereby avoiding slippage and associated pattern distortion. In other words, when the rotation of the printing roll is synchronized with the movement of the web, the speed and trajectory of the surface of the web and the embossed surface are almost the same (i.e., when they are in contact).

FIG. 5 schematically illustrates one embodiment of a portion of a microcontact printing process line 100 that is well suited for forming a SAM on a web 102 that moves in direction A in a roll-to-roll process. The web 102 is moved around a first support 104 (in this example a nip roll) and on at least one elastomeric stamp 106 made of a material such as PDMS. While the web support will generally be referred to herein as a roll, the supports utilized in the apparatus shown in this application may include, but are not limited to, solid rolls, rolls with ball bearings, and air bearings. Rollers, sleeves supported by air or gas, non-contact supports such as air rafts and air strips, air scrapers, and combinations thereof.

In some embodiments, the stamp 106 includes the high aspect ratio embossed pattern elements described above (Fig. 1), although any embossed pattern can be used. In the embodiment of Figure 5, two stamps 106 are mounted on the printing roll 108 to allow for continuous or stepwise continuous printing operations. The stamp 106 can be attached to the printing roller 108 using any suitable technique, including but not limited to double-sided adhesive tape, foam adhesive Pad mounting tape, vacuum based connections, magnetic connections and mechanical connections. The printing roll may have a solid surface that is close to a circular shape and may be selected from, but not limited to, an idler roll having a fixed axis, an idler roll having a moving shaft, an idler roll having a low friction bearing, and a thin metal floating on a thin air layer. An air casing made of a shell, an air sleeve made of a hard metal shell floating on an air layer, a roller driven by a motor, a roller made of a magnetic material, and a pressure between the roller and the stamp is allowed to be lowered. Rolls made of vacuum material, rollers and sleeves that allow mechanical connection of the stamp.

In some embodiments, the surface of the printing roll 108 and the stamp 106 may include an elastomer layer 111 as appropriate. After the web 102 contacts the stamp 106, the web 102 moves around the second nip roll 110 and can then be further processed on the process line 100 as appropriate.

FIG. 6 schematically illustrates another embodiment of a portion of a microcontact printing process line 200 suitable for forming a SAM on a web 202 in a roll-to-roll process. The web 202 is moved around the first stretching roll 204 and on an array of elastomeric stamps 206 made of a material such as PDMS. In some embodiments, the stamp 206 includes the high aspect ratio embossed pattern elements described above (Fig. 1), although any embossed pattern can be used. The stamp 206 is mounted on the printing roller 208. In some embodiments, the surface of the printing roll 208 and the stamp 206 may include an elastomer layer 211 as appropriate. After the web 202 contacts the stamp 206, the web 202 moves around the second stretching roll 210 and may be further processed on the process line 200 as appropriate. In this embodiment, the web 202 is described herein as being stretched between the roll 204 and the roll 210, and the stamp is described herein as contacting the web between the roll 204 and the roll 210.

FIG. 7 schematically illustrates another embodiment of a portion of a microcontact printing process line 300 for printing a SAM on a web 302 in a roll-to-roll process. The web 302 is moved around a single nip 304 and on two elastomeric stamps 306 made of a material such as PDMS. In some embodiments, the stamp 306 includes the high aspect ratio embossed pattern elements described above (Fig. 1), although any embossed pattern can be used. In some embodiments, the surface of the printing roll 308 and the stamp 306 may include an elastomer layer 311 as appropriate. After the web 302 contacts the stamp 306, the web 302 is ready for further processing on the process line 300.

FIG. 8 schematically illustrates another embodiment of a portion of a microcontact printing process line 400 for fabricating a SAM on a web 402 in a roll-to-roll process. The web 402 is wrapped around the nip roller 404 and on an elastomeric stamp 406 made of a material such as PDMS. In some embodiments, the stamp 406 includes the high aspect ratio embossed pattern elements described above (Fig. 1), although any embossed pattern can be used. In some embodiments, the surface of the printing roll 408 and the stamp 406 may include an elastomer layer 411 as appropriate. After the web 402 contacts the stamp 406, the web 402 moves around the stretching roll 410 and may be further processed on the process line 400 as appropriate.

In the embodiments of Figures 5 through 8 above, to reduce printing defects, the tension on the portion of the web that contacts the stamp should be maintained at less than about 10 pounds per line pli. In some embodiments, the tension on the web should be maintained from about 0.1 to about 5 pli, or from about 0.1 to about 2 pli, or from about 0.1 to about 1 pli.

In some of the embodiments of Figures 5 through 8, the web 102 is moved at a speed of from about 0.1 to about 50 mph.

In the apparatus of Figures 5 through 8, the embossed surface can be inked by a variety of techniques. For example, a printing roll on which a stamp is mounted can be placed in an inking tank and filled with an ink composition comprising at least one functionalized molecule. In this procedure, the ink composition is injected into the stamp from the "front side", and the front side herein refers to the stamp side including the pattern element and the embossed surface contacting the surface of the web. The inked sleeve is then removed from the inking tank and the ink loaded printing roll is loaded onto the process line. After printing a predetermined length of web, the spent printing roll is removed (when it includes insufficient ink to form a suitable pattern on the web) and re-inked in the inking tank for later reuse.

Preferably, the inking time (the time the stamp is in contact with the ink during the ink filling process) should be as short as possible while still producing an ink stamp with sufficient printing performance. It is also desirable to have a drying time after the ink is filled as short as possible. Thereafter, two factors make it necessary to have an ink composition which is stable at a high concentration and which can be quickly dried on the surface of the stamp. Rapid evaporation of ink solvent from the surface of the stamp helps to achieve uniform thiol molecules with minimal time and application of pressurized air Distributed on the seal or in the seal. For immersion inking, it is presently preferred that the inking time is less than about 60 minutes, more preferably less than about 45 minutes, more preferably less than about 30 minutes, and even more preferably less than about 15 minutes. After removal and drying, the inking stamp can then be placed in contact with the substrate to contact the raised regions of the embossed patterned surface of the stamp. The organic sulfur compound diffuses from the stamp onto the surface of the substrate, wherein the organic sulfur compounds form a SAM.

Referring again to Figure 5, for example, all of the above inking methods cause the patterned surface 107 of the stamp 106 to be inked to create an "inking surface."

After inking, the stamp 106 is adapted to transfer a pattern of an ink comprising a functionalized molecule, such as an organic sulfur compound, to the surface 120 of the substrate 102. When the ink surface 107 of the stamp 106 includes an array of embossed pattern elements, the inking surface can be in contact with the web surface 120 to transfer the ink pattern to the surface 120, which web surface is substantially flat. The ink pattern transferred to surface 120 is substantially the same as the pattern of raised features in the embossed pattern of ink surface 107 above stamp 106. In such a process, it is said that the ink pattern will be transferred corresponding to the embossed pattern of the ink surface 107 on the stamp 106. When the ink surface 107 above the stamp 106 is substantially flat, the inking surface 107 can contact the surface 120 including the embossed pattern to transfer the ink pattern to the surface 120, wherein the ink pattern is substantially in the embossed pattern of the substrate surface 120 The pattern of the raised features is the same. In such a process, it is said that the ink pattern will be transferred corresponding to the relief pattern of the surface 120 of the web 102.

When the ink surface 107 of the stamp 106 includes the first embossed pattern, the inking surface may contact the surface 120 of the web 102 including the second embossed pattern to transfer the raised features of the first embossed pattern and the second embossed pattern. The contact area between the high features defines an ink pattern (ie, an interactive portion of the embossed pattern). In such a process, the ink pattern is said to be transferred corresponding to the two relief patterns.

The desired printing time (i.e., the duration of contact between the stamp 106 and the surface 120 of the web 102) will depend on various factors including, for example, the concentration or ink solution and the pressure applied to the stamp. In some embodiments, the printing time is less than 1 minute (preferably less than about 30 seconds; more Preferably less than about 10 seconds; optimally less than about 5 seconds).

Referring to Figure 9, in order to reduce the process and line downtime necessary to re-seal the stamp, in any of the above embodiments of Figures 5 through 8, the printing roller 508 can include a fluid coupler 509 for continuously diffusing the ink. Or delivered to the back side of the stamp 506. In this embodiment, the fluid coupler 509 can include a hollow interior region 509A that periodically or continuously supplies an ink composition comprising functionalized molecules. The ink composition diffuses to a printing roll 508, which in this embodiment is a drum made of a permeable or highly porous material. The elastomer layer 511, optionally present on the roller 508, can also penetrate the ink composition, which diffuses into the "back side" of the stamp 506.

Although microcontact printing is the preferred method of fabricating a patterned SAM using the stamp configuration described herein, other patterning methods can be used. Other known methods for patterning SAM include, for example, ink jet printing, using functionalized radical gradients and surface topography oriented assembly.

The patterned SAM formed by the stamp configuration described herein can be used, for example, as a resist that protects the underlying substrate surface area during subsequent patterning steps. For example, a patterned SAM can provide an etch mask. As an etch mask, the surface area of the substrate covered by the SAM (for example, the surface of the metal coating on the polymer film substrate) is protected from the chemical action of the etchant, and the surface area of the substrate not covered by the SAM is protected, thereby allowing The material in the unprotected area is selectively removed (eg, metal is removed from the polymer film substrate). Alternatively, the patterned SAM can provide a plating mask. As a plating mask, the surface area of the substrate covered by the SAM (for example, the surface of the catalytic metal coating on the polymer film substrate) is not catalytic when depositing metal from the electrodeless plating bath, and the surface of the substrate not covered by the SAM The region is still exposed and thus maintains its catalytic activity, allowing selective placement of the electrodeless metal in the unprotected region. A method of applying a patterned SAM as a mask when patterning other materials is known in the art (for example, in U.S. Patent No. 5,512,131).

The operation of various embodiments of the present invention will be further described with respect to the following detailed examples.

Instance

The following examples are for illustrative purposes only and are not intended to unduly limit the scope of the appended claims. Notwithstanding that the numerical ranges and parameters set forth in the broad scope of the present invention are approximations, the values set forth in the particular examples have been reported as much as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviations that are present in the respective test measurement. In no way is meant to limit the application of the theory of equalization to the scope of the patent application, the numerical parameters being interpreted at least in accordance with the number of significant digits reported and by applying the general rounding technique.

All parts, percentages, ratios, and analogs thereof, as provided by the examples and the remainder of the specification, are by weight unless otherwise indicated. The solvents and other reagents used are available from Sigma-Aldrich Chemical Company (Milwaukee, WI).

Example 1

High aspect ratio stamp masters were obtained from Infinite Graphics Inc. (IGI) (St. Paul, MN). The IGI builds the master by spin coating a 5 micron photoresist layer on the glass and imaging the patterned elements having a trapezoidal cross section using gray lithography. The epoxy resin replica (sub-plate) of the stamp master is manufactured by a standard process including a poly(dimethyl methoxide) (PDMS) negative plate for manufacturing a stamp master and a casting ring opposite to the negative plate Oxygen resin. The PDMS stamp was fabricated by casting uncured PDMS on an epoxy sub-plate and curing.

The pattern element on the PDMS stamp has a trapezoidal cross-sectional shape with a bottom width of 5.6 to 7.8 μm, a wall angle of 20° to 30°, a height h of 5 μm, and a width w of the imprinted surface of 2 μm, thereby obtaining about 2.5. Aspect ratio (see for example Figure 2). This seal is hereinafter referred to as a high aspect ratio seal.

A PDMS-like stamp was prepared in which the embossed surface had a width w of 2 μm and a height h of 2 μm, thereby obtaining an aspect ratio of about 0.8. This seal will hereinafter be referred to as a low aspect ratio seal.

Low aspect ratio and high aspect ratio PDMS by ink composition including functionalized molecules The stamp is saturated and then transferred to a spare printing roll having a radius of 9 吋 (about 23 cm). As shown in Tables 1 to 2 below, some of the stamps were mounted on standard solid idle rollers and some were mounted on air jackets, which were thin metal shells floating on the air layer. As shown in Tables 1 to 2 below, in some operations, the stamp is mounted directly on the backup roll, while for other operations, a foam layer is placed between the roll and the stamp. The foam was obtained from 3M Cushion-Mount Plus Plate Mounting Tape, 1120 Tan from 3M, St. Paul, MN.

The ink composition was applied to a silver coated PET of about 100 nm using a PDMS stamp (available under the trade designation ST504 from E.I. DuPont de Nemours, Wilmington, DE). As shown in Tables 1 to 2 below, the web substrate was moved at a speed of 15 ft/min (fpm) and 25 fpm with respect to the stamp, and different web tensions of 1 or 2 lbs/pli were applied to the substrate. A SAM is formed on the surface. Each embossed pattern was evaluated to determine whether line broadening (Y), no line broadening (N), or uncertainty (X) was observed.

The resulting SAM produced by each PDMS stamp has a hexagonal pattern. As shown in Tables 1 through 2, it can be observed that the pattern printed with the high aspect ratio stamp has a significantly reduced print line broadening, less defect count associated with the entrapped particles, and can be printed at higher speeds without having Missing printed area.

High aspect ratio stamps also allow for higher print speeds without the drawbacks associated with air inclusions than low aspect ratio seals. Typically, above the critical printing speed, one of the printed patterns partially disappears because the stamp is no longer in contact with the substrate.

Table 3 below shows a comparison of many air inclusion related defects between a low aspect ratio PDMS stamp (2 μm height h ) and a high aspect ratio PDMS stamp (5 μm height h ). At 15 fpm printing speed, the low aspect ratio stamp shows 14 defects, while the high aspect ratio stamp has 4 or 0 defects.

High aspect ratio seals also reduce defects associated with the presence of dirt particles. Table 3 below shows that when a high aspect ratio seal is used, the number of repeated defects that may be attributed to the particles is reduced from 3 to 1 or 2.

Example 2

During the roll-to-roll microcontact printing process, the roll having the elastomeric stamp is in contact with the substrate on the second roll. The stamp and the substrate are not necessarily in normal contact because the two rollers move at different speeds, causing the substrate to move relative to the stamp, thereby creating drag on the stamp surface and its stamping elements. If the threshold friction value is exceeded, the stamp will slide, resulting in a defective print resolution. A Finite Element Model was developed to simulate the printing process and calculate the amount of drag on the stamp. The modeled results complement the results in Example 1 above. It also shows the advantage of the higher relief stamp in reducing the effect of sliding on defect formation.

A 2D seal cross-section model was fabricated using ANSYS 12.1 commercial software (available from ANSYS Inc., Canonsburg, PA). The model construction consisted of a 500 micron foam adhesive mounted on a printing roll and a 1 mm wide 5 mm stamp with 300 micron spacing between the embossed elements. The embossing element has a wedge shaped trapezoidal cross-sectional shape (Fig. 2) with a vertical angle θ of 13.5. The bottom width is 1.3 μm. We used three different heights h , namely 2.5, 5 and 15 μm to change the aspect ratio. A schematic view of the stamp surface is shown in Figure 10.

In another example, the features are cylinders having a rectangular cross-sectional shape rather than a wedge-shaped trapezoidal shape. The printed substrate is modeled as a rigid surface to which the load is applied. Two types of loads were modeled: the first with a 0.25 pli clamping pressure (N.P.) and the second with N.P. and 2 μm parallel to the relative displacement of the substrate. The model assumes that the imprinting element does not detach from the web during loading (the "standard contact" behavior of the contact element).

A NeoHookean material model was used in which the instant shear modulus of the stamp was G = 896 kPa and the Blatz-Ko compressible foam model, where G = 876 kPa, was used to model both the foam mount and the stamp as a superelastic material.

We have found that the smaller the h value, the less bending the load produces and the more lateral movement of the imprinting element.

Figure 11 is a graph of the drag force produced per 吋 width relative to the substrate displacement. This figure shows that if the drag force exceeds the maximum dry friction between the features and the substrate, the features may slide back to their original position, thereby creating a wider printed line. This possibility is reduced by using higher aspect ratio imprinting elements.

The modeling results show that the imprinting elements on the microcontact printing stamp undergo both compression and bending. The high aspect ratio component undergoes a small force to deform, thereby reducing its likelihood of sliding on the substrate resulting in poor print resolution. Cylindrical rods are structurally highly unstable and are more likely to lose contact with the substrate, thereby possibly skipping the series in the printed SAM pattern.

In this specification, reference is made to "one embodiment", "some embodiments", "one or more The use of the term "exemplary" before the term "embodiment" means that the specific features, structures, materials or characteristics described in connection with the embodiment are included in at least one implementation of the invention. In the example. Thus, phrases such as "in one embodiment", "in some embodiments", "in one embodiment" or "in an embodiment" Means the same embodiment of the invention. In addition, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

Although the present invention has been described in detail with reference to the preferred embodiments of the present invention, it will be understood that Therefore, it should be understood that the invention is not to be construed as being limited to the illustrative embodiments set forth herein. In addition, all publications, published patent applications, and patents cited herein are hereby incorporated by reference in their entirety in their entirety in the extent of the extent Incorporate in general.

Various illustrative embodiments have been described. These and other embodiments are within the scope of the following claims.

Claims (74)

A microcontact printing method comprising: unwinding a web from a support; providing an elastomeric stamp, wherein the stamp is mounted on a printing roll having an air bearing sleeve made of a metal shell floating on the air layer, Further wherein the stamp comprises a bottom surface and a pattern element arrangement having a trapezoidal cross-sectional shape and extending away from the bottom surface, wherein each pattern element comprises an embossed surface having a lateral dimension of less than 5 microns and a height relative to the bottom surface, and wherein An aspect ratio of height to the transverse dimension of at least 1.5; inking the embossed surfaces of the pattern elements with an ink composition comprising functionalized molecules, wherein the functionalized molecules comprise a binder selected for binding to the web a functional group; and contacting the embossed surface of the pattern elements with the major surface of the web for a period of time sufficient to bond the functional group to the web to form the functionalized molecule on the major surface of the web The printing time of the assembled single layer (SAM) corresponding to the pattern element arrangement on the embossed surface. The method of claim 1, further comprising removing the embossed surface from the major surface of the web. The method of claim 1, wherein the aspect ratio of the pattern elements is from 1.5 to 5.0. The method of claim 1, wherein the aspect ratio of the pattern elements is from 1.5 to 3.0. The method of claim 1, wherein the aspect ratio of the pattern elements is from 1.5 to 2.0. The method of claim 1, wherein the web is moved at a speed of at least 10 呎/min. The method of claim 1, wherein the web is moved at a speed of 10 呎/min to 30 呎/min. The method of claim 1, wherein the web is at a speed of from 10 呎/min to 20 呎/min. Move continuously. The method of claim 1, wherein the pattern elements have an embossed surface having a lateral dimension of from 1 micron to 5 microns. The method of claim 1 wherein the pattern elements have an embossed surface having a lateral dimension of less than 1 micron. The method of claim 1, wherein the embossed surface comprises a pattern element having a lateral dimension of from 0.25 micron to 1 micron. The method of claim 1, wherein the printing time is less than 10 seconds. The method of claim 1, wherein the thickness of the SAM on the surface of the web is less than 50 Å. The method of claim 1, wherein the embossed surface comprises poly(dimethyloxane). The method of claim 1, wherein the functionalized molecule is an organosulfur compound. The method of claim 15, wherein the organosulfur compound is selected from at least one of an alkylthiol and an arylthiol. The method of claim 16, wherein the organosulfur compound is an alkyl mercaptan. The method of claim 1, wherein the functional group on the functionalized molecule comprises a thiol. The method of claim 1, wherein the major surface of the web is a metal. The method of claim 19, wherein the metal is silver. The method of claim 1, wherein the pattern elements form a continuous array on the bottom surface of the stamp. The method of claim 1, wherein the pattern elements form a regular array on the bottom surface of the stamp. The method of claim 1, wherein the pattern elements form a screen. The method of claim 23, wherein the screen has an open area fraction of between 90% and 99.75%. The method of claim 23, wherein the screen has an opening between 95% and 99.5% Put the area score. The method of claim 23, wherein the screen is a square. The method of claim 23, wherein the screen is a hexagonal screen. The method of claim 23, wherein the screen has a pseudo-random geometry. The method of claim 23, wherein the pattern elements are curved traces. The method of claim 23, wherein the pattern elements are straight traces. The method of claim 1 wherein the embossed surface is substantially planar and comprises a regular array of pattern elements separated by grooves. The method of claim 1, wherein the web is stretched between the first support and the second support, and wherein the web is between the first support and the second support The tension is at least 0.5 lbs/straight 吋. The method of claim 1, wherein the surface of the web comprises a SAM free region, and the method further comprises etching the SAM free regions. The method of claim 1, wherein the stamp is mounted on a printing roll. The method of claim 34, further comprising a layer of foam material between the printing roll and the stamp. The method of claim 34, wherein the printing roller is cylindrical. The method of claim 36, wherein the stamp has a radius of curvature between 2 cm and 50 cm. The method of claim 36, wherein the stamp has a radius of curvature between 5 cm and 25 cm. The method of claim 34, wherein the printing roller rotation is performed in synchronization with the web movement. A microcontact printing method comprising: stretching a web between a first roll and a second roll with a tension of at least 0.1 pounds per linear nip, wherein the web moves at a speed greater than 10 Å/min; Mounting an elastomeric polymer stamp on a printing roll having an air bearing sleeve made of a metal shell floating on an air layer, further wherein the stamp comprises a bottom surface and has a trapezoidal cross-sectional shape and extends above the bottom surface a pattern element arrangement, wherein the pattern elements each comprise a substantially flat embossed surface having a lateral dimension of from 0.25 micron to 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the lateral dimension is 1.5 to 5.0; inking the imprinted surface with an ink composition comprising an organosulfur compound; contacting the imprinted surface with a major surface of the web between the first roll and the second roll for 0.1 second to 30 a printing time of seconds such that a functional group on the organosulfur compound is bonded to the major surface of the web to provide a self-assembled monolayer (SAM) of the organosulfur compound on the major surface, the self-assembled monolayer Corresponding to the arrangement of the pattern elements on the embossed surface; and removing the embossed surface from the major surface of the web. The method of claim 40, further comprising a layer of elastomeric material between the stamp and the printing roll. The method of claim 40, wherein the aspect ratio of the pattern elements is from 1.5 to 3.0. The method of claim 40, wherein the web is moved between the first roll and the second roll at a speed of 10 Torr/min to 30 呎/min. The method of claim 40, wherein the pattern elements have an embossed surface having a lateral dimension of from 1 micron to 5 microns. The method of claim 40, wherein the pattern elements have an embossed surface having a lateral dimension of less than 1 micron. The method of claim 40, wherein the pattern elements have an embossed surface having a lateral dimension of from 0.25 micron to 1 micron. The method of claim 40, wherein the printing time is less than 10 seconds. The method of claim 40, wherein the embossed surface comprises poly(dimethyloxane). The method of claim 40, wherein the ink composition comprises an alkyl thiol compound. The method of claim 40, wherein the ink composition further comprises an organic solvent. The method of claim 40, wherein the major surface of the web is metal. The method of claim 40, wherein the major surface of the web comprises a SAM free region, and the method further comprises etching the SAM free regions. The method of claim 40, wherein the pattern elements form a screen. The method of claim 53, wherein the screen has an open area fraction of between 90% and 99.75%. The method of claim 53, wherein the screen has an open area fraction of between 95% and 99.5%. The method of claim 53, wherein the screen is a square. The method of claim 53, wherein the screen is a hexagonal screen. The method of claim 53, wherein the screen has a pseudo-random geometry. The method of claim 53, wherein the pattern elements are curved traces. The method of claim 53, wherein the pattern elements are straight traces. A microcontact printing method comprising: unwinding a web from a self-supporting roll, wherein the web moves at a speed greater than 10 Å/min; mounting the poly(dimethyl methoxy oxyalkylene) stamp on having a floating air a printing roll of an air bearing sleeve made of a metal shell on a layer, wherein the stamp comprises a substantially flat bottom surface and a continuous regular array of pattern elements having a trapezoidal cross-sectional shape and extending above the bottom surface, wherein The pattern elements each have a substantially flat embossed surface having a lateral dimension of from 0.25 micron to 5 microns and a height relative to the bottom surface, and wherein the aspect ratio of the height to the lateral dimension is from 1.5 to 5.0; comprising an organic sulfur compound And an ink composition of an organic solvent for inking the embossed surface; Contacting the embossed surface with the major surface of the web for a printing time of from 0.1 second to 30 seconds such that a thiol functional group on the organosulfur compound is bonded to the major surface of the web to be on the major surface Providing a self-assembled monolayer (SAM) of the organosulfur compound corresponding to the array of pattern elements on the embossed surface, wherein the pattern comprises an aspect ratio having a trapezoidal cross-sectional shape and an aspect ratio of less than 1.5 The SAM comprises a reduced incidence of any of the following: a (1) repeating defect; and (2) an air inclusion defect compared to a SAM produced by a poly(dimethyloxane) seal of the component; And removing the embossed surface from the major surface of the web. A microcontact printing system comprising: a first roller and a second roller, and a moving web stretched between the first roller and the second roller; an elastomeric stamp mounted on the air having a float a roll of an air bearing sleeve made of a metal shell on the layer and in contact with the web between the first roll and the second roll, wherein the stamp comprises a bottom surface and has a trapezoidal cross-sectional shape and a pattern element extending above the bottom surface, wherein the pattern elements each comprise a substantially flat embossed surface having a lateral dimension of 0.25 micron to 5 microns and a height relative to the bottom surface, and wherein the height and the lateral dimension An aspect ratio of 1.5 to 5.0; and apparatus for inking the embossed surface with an organosulfur compound having a thiol functional group selected to bind to a major surface of the web to be on the major surface A self-assembled monolayer (SAM) is formed that corresponds to the pattern element arrangement on the embossed surface. The system of claim 62, further comprising an adhesive layer between the roller and the stamp. The system of claim 63, further comprising between the adhesive layer and the seal Layer of elastomeric material. The system of claim 62, wherein the stamp is mounted on an air bearing sleeve. The system of claim 62, wherein the roller continuously fills the ink composition. The system of claim 62, wherein the seal comprises poly(dimethyloxane). The system of claim 62, wherein the pattern elements form a screen. The system of claim 68, wherein the screen has an open area score between 90% and 99.75%. The system of claim 68, wherein the screen has an open area score between 95% and 99.5%. The system of claim 68, wherein the screen is a square. The system of claim 68, wherein the screen is a hexagonal screen. The system of claim 68, wherein the screen has a pseudo-random geometry. The system of claim 68, wherein the pattern elements are curved traces.